The overall objectives of the present program are: 1) The study of the immunoglobulin class of anti-DNA antibodies in SLE. 2) The demonstration of a viral antigen in the lymphocyte membranes of patients with SLE. 3) The effect of transferred thymus cells on established autoimmunity in NZB/NZW F1 hybrid mice when thymosin is given simultaneously. 4) The presence of suppressor T cells in systemic lupus erythematosus. 5) The role of leukocyte inclusions in the granulocytopenia of Felty's syndrome. 6) The mechanism of action of gold salts and penicillamine in rheumatoid arthritis. 7) The development of plaque methods for the measurement of immunoglobulin synthesis of human lymphocytes. BIBLIOGRAPHIC REFERENCES: Ishikawa, H., and Ziff, M., Electron microscopic observations of immunoreactive cells in the rheumatoid synovial membrane, Arthr. Rheumat. 19:1, 1976. Hurd, E.R., Gilliam, J.N., and Ziff, M., The differential effects of cyclophosphamide and 6-MP on the renal disease and skin immunoglobulin deposits of the NZB/NZW F1 hybrid mice, Agents and Actions 6:364-366, 1976.